In the cloning procedure the nucleus of a fully differentiated
donor cell — such as the udder cell used in Dolly’s case — is
inserted into an egg cell after removing the egg’s own nucleus.
The altered egg cell is stimulated to divide, developing into an embryo
made up of cells that genetically match the donor organism that had
supplied the nucleus. Therapeutic or reproductive cloning can be done
when the cloned embryo is about a week old.

Certain animals before Dolly had been cloned using the
nuclei of embryonic cells; Dolly made science history because, for the
first time, adult
cells had been used. Since 1997, several other species — including
mice, goats, cattle, pigs, and cats — have been successfully cloned
from adult cell nuclei, often in order to replicate animals of superior
commercial value (such as cows that are above-average milk producers).
Recent announcements in the press that human clones have been born await
confirmation.

At this conference, advances in both therapeutic and reproductive
cloning will be explained in plain English. Speakers will discuss the
ethical
and legal questions raised by human cloning, whatever its purpose.

What are the potential benefits and risks of human cloning?

In 1997 the birth of the first cloned animal, Dolly the
sheep, unleashed a flood of public curiosity and concern: If animals
could be successfully cloned, why not clone humans? Suddenly this question,
formerly the stuff of science fiction and fantasy, was worthy of serious
consideration — and heated debate.

In the years since Dolly’s birth, interest in human
cloning has focused on its two known uses. Therapeutic cloning involves
harvesting stem
cells from cloned human embryos at a very early stage and directing
the stem cells to differentiate into specific replacement cells. These replacement
cells may then be grafted into human patients. For example, insulin-producing
pancreatic cells may be used to treat diabetes; replacement nerve cells may
be used to treat Parkinson’s disease.
The second, more controversial type of cloning involves using DNA from an
adult or child to create a human being who is genetically identical to that
person.
Such reproductive cloning may enable infertile or gay couples to have children
without the use of a surrogate, or couples with inherited genetic disorders
to avoid passing genetic disease to their children.

Both therapeutic and reproductive cloning, however, have
significant medical and ethical risks. Cloning-based stem cell therapies
carry the risk of tumor
formation, and cloning experiments in animals have been met with alarmingly
high birth defect and mortality rates. Ethical issues associated with human
cloning include embryonic rights, issues of individuality, the impact on
traditional parent-child relationships, and the slippery slope towards “designer” babies
with made-to-order genetic traits.